jace is a cycle-accurate emulation of an enhanced Apple //e. Its modular framework makes it easy for developers to swap out components (video/cpu/etc.) or add new emulated hardware.
If you would like to see the MIDI support in action, here's a recording of the Ultima V introduction: www.youtube.com/watch?v=1G3wQiKtzJ8
A Node.js driver for Apache Cassandra.
A Java package which implements a priority R-Tree, a spatial index.